Application of Chemical Transport Using Micro Wave Plasma to Deposition of Cubic Boron Nitride Film

1.利用石英玻璃等离子体反应器对硼的化学输运进行了初步实验。硼烷是由固体硼颗粒与低压r.f.感应产生的氢等离子体。将硼烷输送到水平放置在反应器中的几个硅晶片衬底上，并在衬底上沉积硼膜。当将少量的氮混合到氢等离子体中时，在每个基板上形成氮化硼膜。通过控制等离子体功率，在离等离子体中心适当距离的衬底上沉积了含sP^3键的硼薄膜.采用石英玻璃制成的立式等离子体反应器沉积氮化硼，获得了较好的效果。将BN管插入石英管中以防止其石英壁被低压感应氢等离子体化学溅射。通过加热衬底并向衬底施加负偏压，沉积纯hBN膜。通过电加热的热钨丝辅助激发气体是有效的，以获得高质量的hBN膜。可以预期，通过控制这些辅助因素，可以检测出形成立方或纤锌矿结构BN薄膜的实验条件.采用一种新型的立式不锈钢等离子体反应器进行了化学输运实验。高激发等离子体产生的高功率微波（MW）放电。但是由于反应堆的一部分过热，很难长时间地向等离子体提供高功率。因此，有必要对反应器的水冷系统进行改进，以存款沉积出高质量、厚的BN薄膜。

1. Preliminary experiments for chemical transport of boron have been carried out by using a conventional horizontal plasma reactor made of quartz glass. Boranes were generated by the reaction between solid boron particles and low pressure r.f. hydrogen plasma inductively generated. Boranes were transported on several silicon wafer substrates placed horizontally in the reactor and boron film was deposited on the substrates. When a small amount of nitrogen was mixed into the hydrogen plasma, boron nitride film was formed on each substrate. By the control of supplying plasma power, a boron film including sP^3 bonding was deposited on the substrate placed at a suitable distance from the center of plasma.2. A vertical plasma reactor made of quartz glass has been used to obtain better results for BN deposition. A BN tube was inserted into the quartz tube to prevent a chemical sputtering of its quartz wall by the low pressure inductive hydrogen plasma. By heating the substrate and applying a negative bias voltage to the substrate, pure hBN film was deposited. An auxiliary excitation of gas by a hot tungsten filament heated electrically was effective to obtain a high quality hBN film. It can be expected that experimental conditions to form BN film with cubic or wurtzite structure will be detected by controlling such auxiliary factors.3. A new vertical type of stainless steel plasma reactor was used as a trial for the chemical transport experiments. Highly excited plasma was generated by a high power microwave(MW) discharge. But it was very difficult to give a high power to plasma for a long time due to superheating of a part of the reactor. So it is necessary to improve a water cooling system of the reactor to deposit a high quality and thick BN film.